Records of Natural Products Articles

 Dried aerial parts of five taxa of Greek Sideritis were subjected to hydrodistillation and the oils obtained were analyzed by using GC and GC-MS. A total of 82 compounds were identified and the analysis showed important differences between the samples not only quantitatively but also qualitatively. The microbial growth inhibitory properties of the essential oils were determined using the broth microdilution method against eight laboratory strains of bacteria - Gram positive: Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Еnterococcus faecalis, Bacillus subtilis and Gram negative: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, a nd two strains of the yeast Candida albicans. The tested essential oils exhibited considerable activity against certain strains of the microorganisms tested, with S. lanata oil presenting MIC values to S. aureus and M. luteuscomparable to those of the reference antibiotics.

The characterization of the volatile compounds of two varieties of Solanum betaceum Cav. by means of headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry ( GC-MS) i s presented. The HS-SPME method for extraction of the volatiles compounds was optimized by using a 2 3 central composite design. Maximum extraction of volatile compounds was achieved by using a divinylbenzene-carboxen-polydimethylsiloxane (DVB/CAR/PDMS) fiber, extraction temperature 76° C, incubation time 44 min, and extraction time of 46 min. The main types of compounds detected in both varieties are terpenoids, followed by aromatics, esters, and aldehydes. Golden-yellow cultivars contained higher levels of esters and terpenes, while the reddish-purple variety contained a significant amount of aromatic compounds. The data structure of the chemical information obtained as well as the relationship between variables was evaluated by means of principal component analysis and cluster analysis.

This study investigated the chemical composition, and antimicrobial and anti -wood-decay fungal activities of the essential oil isolated from the leaf of Litsea acuminata (Blume) Kurata from Taiwan. The essential oil from the fresh leaves of L.acuminata was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC–FID and GC–MS. A total of 48 compounds were identified, representing 100% of the oil. The main components identified were b -caryophyllene (13.0%), t -cadinol (11.1%), a -cadinol (8.6%), α-humulene (7.5%), a -pinene (7.0%), globulol (6.6%), and b -eudesmol (6.1%) . The antimicrobial activity of the oil was tested by the disc diffusion method and micro-broth dilution method against ten microbial species, respectively. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast with inhibition zones of 4 5~ 50 mm to MIC values of 31.25~62.5 μg / mL, respectively. The anti-wood-decay fungal activity of the oil was also evaluated. Results showed that the oil demonstrated excellent activity against four wood-decay-fungi species. For the antimicrobial and anti-wood-decay fungal activities of the oil, the active source compounds were determined to be t -cadinol, a -cadinol, and b -eudesmol.

Syngonanthus bisulcatus Rul., popularly known in Brazil as “sempre-vivas chapadeira”, is a plant of the family Eriocaulaceae, it is found in the states of Minas Gerais and Bahia. In this work, the ethanolic extract (EtOHE), flavonoid-rich (FRF), and flavonoid-deficient (FDF) fractions obtained from scapes of S. bisulcatus were investigated for gastroprotection in both rats and mice. The activity was evaluated in models for induced gastric ulcer (absolute ethanol, stress, non-steroidal anti-inflammatory drugs, and pylorus ligation). The participation of mucus and prostaglandin E 2 were also investigated. Sb-EtOHE (50, 100, and 250 mg/kg, p.o.), Sb-FRF (100 mg/kg, p.o.), and Sb-FDF (100 mg/kg, p.o.) significantly reduced gastric injuries in all models. Sb- FRF altered gastric juice parameters after pylorus ligation. Sb-FRF and Sb-FDF (100 mg/kg each, p.o.) significantly increased the amount of adherent mucus in the gastric mucosa. Sb-FRF maintained the mucosal levels of prostaglandin after the administration of indomethacin. The results indicate that Sb-EtOHE, Sb-FRF and Sb-FDF have significant gastroprotective activity. The observed gastroprotective effects of S.bisulcatus probably involve the participation of both mucus and prostaglandins, integral parts of the gastrointestinal mucosa’s cytoprotective mechanisms against aggressive factors.

Two new germicidins, namely, germicidin D (1) and germicidin E (2), together with two known ones germicidin (3) and acetamide (4) were isolated from the endophytic Streptomyces sp. A00122 of Camptotheca acuminata. The structures of the isolated compounds were elucidated by spectroscopic analyses, including 1D- and 2D-NMR experiments HR-Q-TOF mass spectrometry. Antimicrobial assays with compounds 1 and 2 were carried out; they had no shown effect on the growth of tested bacteria or yeasts.

The present study was performed to evaluate antifungal activities of leaf essential oils from Eucalyptus camaldulensis Dehnh. originating from Thailand against 9 fungal strains. The leaf samples were collected from 3 different clones. The fungi examined in this study were (1) household molds: Aspergillus niger , Cladosporium cladosporioides, Chaetomium globosum and Penicillium citrinum, (2) wood rot fungi: Fomitopsis palustris and Trametes versicolor, (3) plant pathogenic fungi: Fusarium oxysporum, Thanatephorus cucumeris and Rhizopus oryzae. The results revealed that E. camaldulensis leaf oils provided 100% inhibition of the mycelial growth of T. cucumeris (5 mg/m L ), and C. globosum (10 mg/m L ). No inhibition effect was observed against R. oryzae even at the concentration of 10 mg/m L . A medium to low inhibitory activities against the mycelial growth of the six other fungi were found. The essential oils of E. camaldulensis leaf have potency as an antimicrobial agent especially against seedling blight pathogens and it could also act as moderate agents against household molds and wood rot fungi. Therefore, even if they need relatively higher concentration for the controlling agents, they deserve as the alternatives to hazardous synthetic fungicides from the ecological viewpoints.

 The essential oils of Greek Ferula communis subsp. communis from different plant parts were obtained by hydrodistillation and analyzed by means of GC and GC-MS. Ninety three compounds were identified in the total essential oils. Sesqui terpenes were the most dominant class of compounds in the leaves and inflorescences oils, while infructescences oils were rich in monoterpenes with α-pinene (35.2-40.6%) being the dominant component.

Phytochemical investigation of Strobilanthes crispus has led to the isolation of 1-heptacosanol (1), tetracosanoic acid (2), stigmasterol (3) from the hexane extract, a mixture of four C 20-C 24 fatty acid esters of β-amyrin (4), taraxerol (5), taraxerone (6), a mixture of two C 22 and C 24 fatty acid esters of taraxerol (7) from the dichloromethane extract, 4-acetyl-2,7-dihydroxy-1,4,8-triphenyloctane-3,5-dione (8) and stigmasterol β- D -glucopyranoside (9) from the methanol extract. T he dichloromethane and methanol crude extracts together with the isolated compounds (4- 9) were tested for antibacterial activity using the determination of minimum inhibitory concentration assay and acetylcholinesterase inhibitory activity using the micro-plate assay . The majority of the samples tested indicated good activity against the Gram-positive bacteria (7.8─125.0 μg/mL), and moderate to weak activity against the Gram-negative bacteria (31.0─250.0 μg/mL) employed. Moderate to weak activity was observed against acetylcholinesterase. Compound (8)showedexcellentantibacterialactivity against Bacillus subtilis and Staphylococcus aureus , with MIC values of 15.6 and 7.8 μg/mL, respectively, and significant activity against Escherichia coli and Salmonella typhimurium , with MIC values of 62.5 and 31.0 μg/mL, respectively. Compound (8) also showed the highest acetylcholinesterase inhibitory activity, with an IC 50 value of 31.0 μg/mL. This is the first report describing the antibacterial and acetylcholinesterase inhibitory activities of S. crispus on the basis of the isolated constituents. This research work has provided scientific proof of the traditional medicinal use of the leaves of S. crispus.

Betulinic acid (1), 5-hydroxy-3-methoxyxanthone (2), 1,6-dihydroxy-7-methoxyxanthone (3), daucosterol (4), bijaponicaxanthone C (5), hypercalin C (6), 1-hydroxy-6,7-dimethoxyxanthone (7), cadensin D (8) and 5-hydroxy-1,3-dimethoxyxanthone (9) were isolated from the roots of Hypericum riparium. These compounds are reported for the first time from this plant. The extracts and two of the isolated compounds (2 and 8) exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC = 0.97-250 µg/mL). In addition, the brine-shrimp (Artemia salina) lethality bioassay of compound 6 showed potent cytotoxicity with LD 50 of 3.23 µg/mL.